[DonVoigt]

Originally Posted by sheepherder

Don, this is the first frame ear I have seen pictures of that shows definitive [& rough!] surface grind marks. My own Luger ears are all lacking any tool marks, whether mill, grinder, or polish. I have to wonder what the Erma people thought needed additional grinding...Unusual to see this pattern of grind marks, it indicates some kind of horizontal grind fixture, rather than a vertical rotary grinder...

Good question, but I have no idea.
Maybe a dent that needed cleaning up?
Another one of those curious "un-knowables".